Recallab › Question bank › Surgery › Arterial Disorders › #50070
Abdominal aortic aneurysm surveillance
A 70-year-old man has an incidental finding on abdominal ultrasound of an infrarenal aortic aneurysm measuring 4.3 cm in maximum diameter. He has no abdominal or back pain, and no tenderness. He is a former smoker with controlled hypertension. What is the most appropriate management?
- correctA. Regular ultrasound surveillance with risk factor modification
- B. Open surgical repair now
- C. Endovascular aneurysm repair now
- D. Urgent computed tomography angiography and repair within 24 hours
Explanation
Key fact
Repair an asymptomatic abdominal aortic aneurysm at 5.5 cm, or if it grows more than 1 cm in a year, or if it becomes symptomatic.
Regular ultrasound surveillance with risk factor modification. At 4.3 cm the risk of rupture is well below the risk of repair.
Why
Rupture risk rises steeply only once the diameter passes about 5.5 cm.
Below that, operative mortality exceeds the annual rupture risk.
Two large trials showed no survival benefit from early repair of small aneurysms.
Surveillance intervals shorten as the aneurysm grows.
Stopping smoking and controlling blood pressure slow expansion.
Five and a half, or a centimetre a year, or it hurts
Why not the others
- B. Open surgical repair now — exposes him to an operative mortality of several per cent for an aneurysm unlikely to rupture.
- C. Endovascular aneurysm repair now — carries lower early mortality but the same argument applies, plus a lifetime of surveillance for endoleak.
- D. Urgent computed tomography angiography and repair within 24 hours — is the response to a symptomatic or tender aneurysm. He has neither.
Remember
Five and a half, or a centimetre a year, or it hurts. Any one of the three and it comes out.
Go deeper
The threshold is lower in women, at about 5.0 cm, because their aortas are smaller and rupture at smaller diameters.
A tender aneurysm of any size is treated as a contained or impending rupture.
The triad of back or abdominal pain, hypotension and a pulsatile mass is rupture until proved otherwise - and a stable patient still goes straight to computed tomography.
Bailey & Love's Short Practice of Surgery, 28th ed. (CRC Press, 2023); Sabiston Textbook of Surgery, 22nd ed. (Elsevier, 2025).